The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Automobiles and light trucks of current manufacture contain many components that are acquired in packaged form from outside suppliers. The packaged components reduce the time required to assemble automotive vehicles and further improve the quality of the vehicles by eliminating critical adjustments from the assembly line. So-called “wheel ends” represent one type of packaged component that has facilitated the assembly of automotive vehicles.
Traditionally, a solid rear axle shaft coupled a differential to a wheel end. The wheel end includes hub with a hollow spindle having an orifice with internal splines for receiving and mating with a splined-end of the axle shaft. The axle shaft includes a threaded end for receiving a nut to hold the wheel end onto the axle shaft and for supporting thrust loads. In these arrangements, the axle shaft must have a substantial size, strength and weight for supporting the transfer of torque as well as providing structural support to the wheel end. Consequently, the hub spindle must also have substantial diameter, size and weight.
Some automotive vehicles, particularly light trucks and sport utility vehicles, use solid rear axles of the semi-floating variety to transfer torque to the driving wheels for such vehicles. The typical semi-floating rear axle has axle tubes that are fastened to and extend from an axle center that contains differential gearing. The gearing drives two axle shafts that extend through the tubes and at their ends are provided with hubs to which road wheels are secured along with brake disks or drums. In such arrangements, a solid rear axle housed in an axle tube that is connected at one end to a differential and at the other end to a rear wheel end. A housing at the wheel end is bolted to the axle tube for providing thrust support in both directions. A solid axle shaft within the axle tube transfers rotational drive torque from the differential drive to a drive hub. As such, the axle shaft typically has a substantial diameter for ensuring the transfer of torque to the hub. The hub includes a hollow spindle that is mounted within the housing by antifriction bearings for providing near frictionless rotation of the hub within the housing. The hub has a driving flange on which a wheel is mounted. The spindle of the hub is hollow in that it includes a center hole or orifice having inner splines for receiving and engaging mating splines on the outside of an end of the axle shaft.
However, in current wheel end assemblies not only does the axle shaft have to have substantial diameter, but the spindle of the hub must have substantial diameter for receiving within its hollow body the axle shaft and for defining the internal splines for coupling to the axle shaft. As such, the antifriction bearings that surround the hub spindle to provide support to the spindle and the hub must also have substantial diameter. Consequently, the housing supporting the antifriction bearings must also have substantial diameter as required by the outer dimensions of the hollow spindle.